In recent years, simulation of biological systems has been attracting attention. As an example of simulation of biological systems, simulation of the motion of organs such as the heart is often performed. In this case, a model of the organ is generated as input data. For simulating an organ of an individual patient, a model conforming to the shape of the organ of the patient is generated. However, since it is difficult to directly view the organ of the patient, the shape of the organ is determined from tomographic images of the organ, for example. Then, a three-dimensional (3D) model is generated on the basis of the determined shape. For instance, a 3D template deformation method has been disclosed that facilitates generation of a 3D shape model of the heart of a patient and blood vessels around the heart (see, for example, Japanese Laid-open Patent Publication No. 2011-200549).
However, it is difficult to accurately reproduce the shape of an organ as a 3D model from tomographic images of the organ.
For example, it is assumed that a 3D model of the heart of a patient is generated by deforming a 3D model which is prepared as a template of the shape of the heart. In this case, in a first deformation process, the position of a valve annulus (the frame of a valve) in the template is adjusted to match the shape of the heart. The first deformation process greatly affects the subsequent deformation process, and therefore needs to be performed accurately. According to a conventional method, in the case of matching the position of a valve annulus in the template to the shape of the heart of a patient, points are manually set in the template so as to correspond to respective points on a valve annulus in tomographic images of the heart. Then, the template is deformed such that the points in the template match the corresponding points on the valve annulus in the tomographic images. However, since the points in the template corresponding to the points on the valve annulus in the tomographic images are set manually, the relative positional relationship between, for example, valve annuli might be inconsistent in three dimensions, and therefore the deformed model might be distorted.